Input Current Range Research Articles

Design, Control, and Analysis of a Novel Grid-Interfaced Switched-Boost Dual T-Type Five-Level Inverter With Common-Ground Concept

Multilevel inverters with a common-ground structure and voltage step-up feature are beneficial for transformerless grid-connected photovoltaic applications. In this article, a novel topology of such converters with a five-level output voltage generation is presented. The proposed topology comprises of an integrated switched-boost (SB) module and a dual T-type (D2T) cell constructed with 10 power switches (six unidirectional and two bidirectional). An inductor in the integrated SB module is used to boost the voltage across two involved capacitors of the D2T cell. Therefore, a desirable ac voltage magnitude for the grid-connected application can be achieved over a wide range of input voltage changes. Current stress is also kept within a permissible input current range by the soft-charging operation of the involved capacitors through the inductor. A corresponding dead-beat continuous-current-control-set controller with a sinusoidal PWM modulator is implemented for controlling the real and reactive powers. The controller has an added benefit of achieving constant switching frequency for power switches. Circuit description, theoretical analyses, and comparative study are discussed. Simulation and experimental results are also presented to confirm the feasibility and correctness of the proposed topology.

A 50μW Fully Differential Interface Amplifier With a Current Steering Class AB Output Stage for PPG and NIRS Recordings

This presents a low-power fully differential optical sensor interface amplifier for photoplethysmography (PPG) and near infrared spectroscopy (NIRS) recordings. The proposed amplifier employs a stacked current reuse input stage that provides a DC biasing voltage for the photodiode, reducing the parasitic capacitance. The output stage exploits a fully differential current steering class AB topology with a self-regulated common mode voltage, providing a $70\mu \text{A}$ input current range with minimized quiescent current. Moreover, the interface amplifier can be reconfigured as either single-ended mode suitable for photo detectors biased at a high voltage or fully differential mode for those biased at a low voltage. This amplifier is implemented in a standard $0.18\mu \text{m}$ CMOS process and characterized experimentally. Measurement results show that, with a 1.5V supply, the amplifier can provide up to 1V biasing voltage for the photodiode and consumes a static power of around $50\mu \text{W}$ . It achieves a dynamic range of 97dB in fully differential mode with an input referred noise of 67pArms in 32Hz band and 102dB in single -ended mode with an input referred noise of 582pArms.

A Glucose Concentration Detector With Wide-Range Converter Used on Livestock

In this study, a glucose concentration detector was used to detect the glucose concentration in the drinking solution of livestock for the first time. The detector comprised a glucose sensor and a proposed wide-range glucose concentration converter. The proposed wide-range glucose concentration converter can linearly convert the concentration of glucose into a duty cycle. To allow them to be used in various glucose sensors, scaling circuits were added to the glucose concentration detector to enable adaptation to the currents generated by glucose sensors. All functions of the glucose sensor and proposed wide-range glucose concentration converter were proved by conducting measurements. The measured input current range of the proposed converter was 30 nA to 3 mA. This ensured that a wide dynamic range of input currents of 100 dB was guaranteed. A glucose concentration in the range of 5%–30% could be detected, and the corresponding duty cycle of the proposed detector was in the range of 4.67%–89.5%. The maximum linear error was −0.75%. The sensitivity of the proposed detector was 3.39%/%, and the chip size was 1.13 $\times$ 1.13 mm2. Finally, an experiment to detect the glucose concentration in the drinking solution of livestock was conducted. The results revealed that the proposed converter was suitable for glucose concentration detection.

Design of a Water Salinity Difference Detector for Monitoring Instantaneous Salinity Changes in Aquaculture

A water salinity difference detector is proposed herein for monitoring instantaneous salinity changes in aquaculture. The detector comprises a water salinity difference sensor and a proposed water salinity difference sensor transducer. The proposed sensor transducer can linearly convert the water salinity difference into a frequency output. Moreover, a technique for automatically changing the sensitivity of the proposed sensor transducer is presented. By using this functionality, the instantaneous salinity changes can be detected with high sensitivity when aquatic organisms are in water with high salinity difference. The performance of the proposed water salinity difference detector was verified through measurements. The measured input current range of the proposed sensor transducer was 12.5– $60~\mu \text{A}$ , and the sensitivities of 1.6, 2.38, 3.17, and 4.05 kHz/ $\mu \text{A}$ were automatically adjusted. The water salinity difference ranged from 7.5 to 35‰, and the sensitivities of 2.492, 2.72, and 3.56 kHz/‰ were also successfully guaranteed. The maximum linear error measured was 0.47%, and the chip area was $1.49\times1.49$ mm2. Finally, a case for monitoring instantaneous salinity changes in aquaculture was developed through experimentation. The results of this study revealed that the proposed chip is suitable for detecting water salinity difference.

Low-Voltage Flipped Voltage Follower Cell Based Current Mirrors for High Frequency Applications

The paper proposes low-voltage current mirrors namely low-voltage current mirror (LVCM) and flipped voltage follower based low-voltage current mirror (FVFLVCM) with high bandwidth. The stability of the proposed circuits has been performed by time-domain approach and frequency domain approach using Routh–Hurwitz stability criteria and phase margin calculations, respectively. The bandwidth of the proposed FVFLVCM has also been enhanced using resistive compensation technique. The proposed LVCM and FVFLVCM have wide input current range of 0–100 µA and 0–150 µA, low DC error of 5.9% and 4.9%, low DC power dissipation of 110.39 µW and 99 µW, high bandwidth of 367 MHz and 624 MHz, low input impedance of 16.3 KΩ and 12.3 KΩ, low THD of 0.26% and 1% and low output noise of 2.25 nA and 2.83 nA over 100 MHz, respectively. The results have been simulated using SPICE in the TSMC 0.18 µm CMOS technology and are presented to validate the effectiveness of the proposed current mirrors.

A Self-Powered P-SSHI Interface Circuit with Adaptive On-Resistance Active Diode for PEH

This paper presents a two-stage synchronous rectifier interface circuit for piezoelectric energy harvesting (PEH) system. The proposed rectifier includes a first-stage negative voltage converter, a second-stage adaptive on-resistance active diode, and combines a precise switch-on-time controlled P-SSHI circuit. The traditional active two-stage synchronous rectifier has lower current detection accuracy and hardly achieves high efficiency rectification over a wide input current range. An adaptive on-resistance active diode (AOR active diode) is proposed to replace the traditional active diode to achieve higher current zero-crossing detection accuracy, improve the input current range and the output power of the rectifier. The proposed diode allows the rectifier to maintain high rectification efficiency over a wider input current range. Further, a parallel synchronized switch harvesting on inductor (P-SSHI) with precise switch-on-time controlled circuit is proposed to achieve higher voltage flipping efficiency and improve the power extraction capability of the rectifier. By using the AOR active diode and the P-SSHI with precise switch-on-time controlled circuit, a good performance improvement has been achieved for the proposed interface circuit. The design is fabricated in an SMIC 0.35[Formula: see text][Formula: see text]m standard CMOS technology with a die size of [Formula: see text][Formula: see text]mm2. The simulation results indicate that the proposed circuit achieves more than 80% power converting efficiency and its peak efficiency is 85%. The current zero-crossing detection accuracy of the proposed AOR active diode is less than 10[Formula: see text][Formula: see text]A. The proposed PEH interface circuit extracts up to 2.81 times more output power compared with a traditional rectifier. The voltage flipping efficiency of the P-SSHI circuit is up to 90%, which can effectively improve the power extraction capability of the rectifier. Moreover, the proposed circuit can be self-powered and cold started up.

A low-voltage gain boosting-based current mirror with high input/output dynamic range

This paper presents a bulk-driven current mirror circuit based on the gain-boosting technique to achieve high input/output dynamic range and high output resistance. The bulk-driven based diode-connected transistor at the input removes the threshold voltage limitation to provide low headroom voltage on the basic transistors. In addition, the auxiliary circuit used in the first gain-boosting structure is a current mode amplifier that is driven by draining current from the main circuit to remove threshold voltage limitation on the input/output swing. In order to achieve higher output resistance, the second gain-boosting structure includes a voltage mode amplifier without creating any limitation on the output swing. Simulation results in a 0.18 ​μm CMOS technology show a maximum output voltage swing of 0.9 ​V under a 1 ​V supply, while the input and output resistances are 68.3 ​Ω and 10.5 ​GΩ, respectively. The current transfer error also changes between −0.085% and +0.075% for an input current range of 1000 ​μA.

High Precision Low-Voltage WTA/LTA Circuit for Signal Processing Applications

The paper proposes low-voltage current mode winner takes all (WTA)/loser takes all (LTA) circuit which detects maximum and minimum values from the given current inputs simultaneously. The circuit is developed using high swing self-biased cascode current mirror and a subtractor circuit. The cascode current mirror is used to improve the accuracy of current mirroring action over a wide input current range and subtractor circuit is used to compute the difference of two input currents. The proposed circuit operates at supply voltage of 1.1 V with high precision. The output current is mirrored with transfer error of 0.03% while input current is varying from 0 to 40 μA. Simulations have been performed using SPICE level 53 (TSMC) parameters in 0.18 μm CMOS technology. Some of the applications of the proposed WTA/LTA circuit such as half wave rectifier, full wave rectifier and modulus circuit have also been presented to show the effectiveness of the proposed circuit.

High step‐up single‐phase‐switched Z ‐source inverter: steady‐state analysis and cost evaluation

This study presents a high step-up switched Z -source inverter. Only by using one more inductor and capacitor in comparison with switched boost inverter, the presented inverter reaches various advantages such as including high boost factor, reduced range of duty cycle and continuous input current. These features make it suitable to use in different applications such as photovoltaic system to increase the voltage level. In this study, a comprehensive analysis of the presented inverter in shoot through (ST) and non-ST operation modes are given. This study also elaborates an appropriate switching pattern for the proposed inverter. There is also a comprehensive comparison and cost evaluation of the proposed structure with conventional structures. Cost and power efficiency comparisons are evaluated by the design considerations of ZSIs in the same condition. Finally, in order to reconfirm the analyses, the experimental results of the laboratory prototype are presented.

A Citric Acid Concentration Detector Used With Chicken Poultry Drinking Solution

In this paper, a citric acid concentration detector was newly used with chicken poultry drinking solution. It consisted of a citric acid sensor and a proposed citric acid concentration sensor transducer. The proposed citric acid concentration sensor transducer can linearly convert citric acid concentration into a duty cycle output. Compared with the traditional analog outputs, the proposed detector could have less noise sensitivity due to its digital output. Moreover, an adjustment technique to vary the input currents of the proposed sensor transducer is also presented. The functionality matching the different current ranges of other citric acid sensors could thus be easily achieved. All functions of the citric acid sensor and proposed citric acid concentration sensor transducer were verified through measurements. The measured input current dynamic range of the proposed sensor transducer was from 0.1 μA to 8.77 mA (i.e., 98.86 dB). The citric acid concentration ranged from 1% to 15%, with the corresponding duty cycle ranging from 51.3% to 96.3%. The maximum linear error measured was 0.28%. Sensitivity was measured at 3.2%/%, and the chip area was 1.49 × 1.49 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Finally, an experiment for detecting the citric acid concentration of chicken poultry drinking solution was conducted, proving that the proposed chip was suitable for citric acid concentration detection.

Design of fast adaptive readout system for wire scanners

A new wide-range fast readout system capable of adaptive identification is designed for wire scanners, which are used to measure beam profiles and emittance. This system is capable of handling varying current signals with Gaussian distributions and current pulses up to 1000 counts/s, as well as an input current range of 1 nA–1 mA. When tested, the resolution was found to exceed 3.68% for full scale, the nonlinearity was found to be less than 0.11%, and the measurement sensibility was found to be less than 5 pA. We believe that the system will play a crucial role in improving the measurement accuracy of beam diagnosis and the efficiency of accelerator operation, as well as decreasing the time required for beam tuning. This system was applied to the beam diagnosis of an injector II prototype for an accelerator-driven subcritical system and produced excellent measurement results. A description of the adaptive fast readout system for wire scanners is presented in this paper.

Current mode pulse width modulation/pulse position modulation based on phase lock loop

Abstract In this paper, the fully integrated CMOS current mode PLL with current input injects at the place of input or output of the loop filter without summing amplifier circuit. It functions as PPM and PWM circuit is present. In addition, its frequency response is an analysis which electronic tuning BPF and LPF are obtained. The proposed circuit has been designed with 0.18 μm CMOS technology. The simulation results of this circuit can be operated at 2.5 V supply voltage, at center frequency 100 MHz. The linear range of input current can be adjusted from 43 μA to 109 μA, and the corresponding duty cycle of pulse width output is from 93% to 16% and the normalized pulse position is from 0.93 to 0.16. The power dissipation of this circuit is 4.68 mW with the total chip area is 28 μm × 60 μm.

Design and characterization of a 64 channels ASIC front-end electronics for high-flux particle beam detectors

A new wide-input range 64-channels current-to-frequency converter ASIC has been developed and characterized for applications in beam monitoring of therapeutic particle beams. This chip, named TERA09, has been designed to extend the input current range, compared to the previous versions of the chip, for dealing with high-flux pulsed beams. A particular care was devoted in achieving a good conversion linearity over a wide bipolar input current range. Using a charge quantum of 200 fC, a linearity within ±2% for an input current range between 3 nA and 12 μA is obtained for individual channels, with a gain spread among the channels of about 3%. By connecting all the 64 channels of the chip to a common input, the current range can be increased 64 times preserving a linearity within ±3% in the range between and 20 μA and 750 μA.

Novel CMOS Current Inverting Differential Input Transconductance Amplifier and Its Application

This paper presents the complementary metal oxide semiconductor (CMOS) implementation of active building block, namely, current inverting differential input transconductance amplifier (CIDITA) along with its performance parameters. The detailed study of the proposed CMOS CIDITA has been incorporated. The presented study shows the good performance of CIDITA in terms of good bandwidth range, good linear range of input current, high accuracy and low operating voltage. A new circuit of single active element-based quadrature oscillator is further realized to explore the workability of CIDITA. The proposed circuit of quadrature oscillator employs two grounded capacitors, one resistor and single CIDITA. The proposed quadrature oscillator provides both quadrature current outputs and quadrature voltage outputs simultaneously. The frequency of oscillation of the proposed quadrature oscillator is electronically controllable. The possible practical realization of the CIDITA using commercially available ICs is also given. HSPICE simulation results using 0.18[Formula: see text][Formula: see text]m CMOS parameters are given to validate the proposed theory.

Low voltage high performance bulk driven quasi-floating gate based self-biased cascode current mirror

A low voltage high performance self-biased cascode current mirror in terms of output resistance and bandwidth is proposed in this paper. The proposed current mirror enhances the output resistance in range of mega ohms and also shows a significant improvement in bandwidth compared to prior arts. The current mirror is designed using bulk-driven technique which helps it to operate at very low supply voltage of ±0.2V. To achieve high output resistance, the proposed current mirror uses the super cascode stage at its output. Furthermore, an external capacitor is used which accounts for increasing the bandwidth. Small-signal analysis carried proves the improvement achieved by proposed architecture. The current mirror operates well for wide input current range from 0 to 200μA with good linearity and shows the bandwidth of 415MHz. The observed input and output resistance is 300Ω and 212MΩ respectively. Further, the THD and mismatch analysis is carried to prove the robustness of proposed current mirror. The complete analysis of proposed current mirror is shown using HSpice simulations on UMC 0.18μm technology.

A CMOS Amperometric System for Multi-Neurotransmitter Detection

In vivo multi-target and selective concentration monitoring of neurotransmitters can help to unravel the brain chemical complex signaling interplay. This paper presents a dedicated integrated potentiostat transducer circuit and its selective electrode interface. A custom 2-electrode time-based potentiostat circuit was fabricated with 0.13 μm CMOS technology and provides a wide dynamic input current range of 20 pA to 600 nA with 56 μ W, for a minimum sampling frequency of 1.25 kHz. A multi-working electrode chip is functionalized with carbon nanotubes (CNT)-based chemical coatings that offer high sensitivity and selectivity towards electroactive dopamine and non-electroactive glutamate. The prototype was experimentally tested with different concentrations levels of both neurotransmitter types, and results were similar to measurements with a commercially available potentiostat. This paper validates the functionality of the proposed biosensor, and demonstrates its potential for the selective detection of a large number of neurochemicals.

A Consistent Model for Lazzaro Winner-Take-All Circuit With Invariant Subthreshold Behavior.

This paper considers the basic Lazzaro winner-take-all analog computing circuit with N current inputs, N voltage outputs, and a bias current. Motivated by low-power applications, we find a mathematical accurate model of the network when all MOS devices remain inside the subthreshold region all along the transient. This involves analytical inequalities relating the range of admissible input currents to transistor parameters, to supply voltage, and to bias current. The restrictions are sufficiently weak to allow extra demands of functionality or performance. The technical novelty here is that by a slight cut of the maximal subthreshold domain and by choosing proper coordinates, we get a ordinary differential equation invariance problem on a rectangle of ℜN+1 space which is analytically tractable. A more precise localization of the asymptotically stable steady state inside the region of interest is also inferred. Although the work is mainly theoretical, an effort to infer simple, interpretable formulas useful for synthesis has been made. The results are numerically verified and their feasibility is discussed in detail. The subject matter is new and it is worth extending it to larger classes of circuits with regional behavior.

A Highly Digital VCO-Based ADC Architecture for Current Sensing Applications

This paper presents a voltage-controlled oscillator (VCO) based current to digital converter for sensor readout applications. Second order noise shaping of the quantization error is achieved by using implicit capacitance of the sensor to realize a passive integrator and a VCO-based quantizer. The non-linearity in voltage to frequency conversion of the VCO is tackled by placing the VCO in a loop consisting of a simple digital IIR filter and a passive integrator. The IIR filter provides large gain within the signal bandwidth and suppresses VCO input swing. As a result, non-linearity of the VCO is not exercised, thus greatly improving the proposed architecture's immunity to VCO nonlinearity. The use of a digital filter instead of an analog loop filter eases the design and makes it scaling friendly. Designed for an ambient light sensor application, the proposed circuit achieves 900 pA accuracy over an input current range of 4 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu$</tex></formula> A. Fabricated in a 0.18 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu$</tex> </formula> m CMOS process, the readout circuit consumes a total of 77.8 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu$</tex> </formula> A current, and occupies an active area of 0.36 mm <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$^2$</tex></formula> .

A Wireless FSCV Monitoring IC With Analog Background Subtraction and UWB Telemetry.

A 30-μW wireless fast-scan cyclic voltammetry monitoring integrated circuit for ultra-wideband (UWB) transmission of dopamine release events in freely-behaving small animals is presented. On-chip integration of analog background subtraction and UWB telemetry yields a 32-fold increase in resolution versus standard Nyquist-rate conversion alone, near a four-fold decrease in the volume of uplink data versus single-bit, third-order, delta-sigma modulation, and more than a 20-fold reduction in transmit power versus narrowband transmission for low data rates. The 1.5- mm(2) chip, which was fabricated in 65-nm CMOS technology, consists of a low-noise potentiostat frontend, a two-step analog-to-digital converter (ADC), and an impulse-radio UWB transmitter (TX). The duty-cycled frontend and ADC/UWB-TX blocks draw 4 μA and 15 μA from 3-V and 1.2-V supplies, respectively. The chip achieves an input-referred current noise of 92 pA(rms) and an input current range of ±430 nA at a conversion rate of 10 kHz. The packaged device operates from a 3-V coin-cell battery, measures 4.7 × 1.9 cm(2), weighs 4.3 g (including the battery and antenna), and can be carried by small animals. The system was validated by wirelessly recording flow-injection of dopamine with concentrations in the range of 250 nM to 1 μM with a carbon-fiber microelectrode (CFM) using 300-V/s FSCV.

Design of current sensor using a magnetorheological fluid in shear mode

A new approach to measure the direct current (dc) using magnetorheological (MR) fluids with a resonance concept is proposed in this work. The current measurement system is designed using a piezolaminated cantilever beam coupled with an electromagnetic coil-based MR fluid shearing set-up. The cantilever beam is maintained at resonance using simple closed-loop electronics. The current-induced magnetic field produced by the coil changes the viscosity of the MR fluids and produces an additional stiffness to the resonating cantilever beam. The shift in resonant frequency due to the change in viscosity of the MR fluid is measured, and the shift in frequency is related to the input electrical current to the coil. The analytical model of the current measurement system is derived, and the results are compared with the experimental results. The resonance-based current measurement system is evaluated for the input current range of 0 to 1 A.